Redo indexing mechanism (#16)

* Bumped up the line length because I fear no man

* Refactored indexing

Previously, indexing worked by collecting the video IDs of only videos
that matched indexing criteria. This new model instead stores ALL videos
for a given source, but will only _download_ videos that meet that criteria.
This lets us backfill without indexing, makes it easier to add in other
backends, lets us download one-off videos for a source that don't quite
meet criteria, you name it.

* Updated media finders to respect format filters; Added credo file

lib/pinchflat_web/components/layouts/partials/sidebar.html.heex

@@ -17,11 +17,7 @@
         <ul class="mb-6 flex flex-col gap-1.5">
           <.sidebar_item icon="hero-tv" text="Sources" navigate={~p"/sources"} />
 
-          <.sidebar_item
-            icon="hero-adjustments-vertical"
-            text="Media Profiles"
-            navigate={~p"/media_profiles"}
-          />
+          <.sidebar_item icon="hero-adjustments-vertical" text="Media Profiles" navigate={~p"/media_profiles"} />
         </ul>
       </div>
     </nav>